Which translates into "Earth 3D View isn't available". The text is a link which points to https://support.google.com/maps/answer/3096703.
Up to that point, the 3D View worked without problem. Changing the default useragent for google.com to emulate Firefox 91.0 (the latest version) makes no difference at all, either in a private window or in a clean setup of Pale Moon Portable 29.4.0 (with a clean profile, of course).
Is this something that can be solved by an updated useragent, or is the change deeper?